pipoint/cycle.go

44 lines
1.1 KiB
Go

// Copyright 2017 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
package pipoint
import (
"math"
"juju.nz/x/pipoint/param"
"juju.nz/x/pipoint/util"
)
// CycleState cycles the pan/tilt in a circle.
type CycleState struct {
pi *PiPoint
cycle float64
}
func (s *CycleState) Name() string {
return "Cycle"
}
// Update reacts to changes in parameters.
func (s *CycleState) Update(param *param.Param) {
switch param {
case s.pi.tick:
s.cycle += 0.02
s.pi.pan.Set(util.Scale(math.Cos(s.cycle), -1, 1, -math.Pi/2, math.Pi/2))
s.pi.tilt.Set(util.Scale(math.Sin(s.cycle), -1, 1, -math.Pi/2, 0))
}
}